Determination of penetration and protection of fatty acids in bleached hair according to the fatty acid chain length and the application to understanding the protective effects of MCT oil and coconut oil

Hair treatments containing vegetable oils protect the damaged hair by surface coating and by penetrating in hair thereby filling the gaps caused by oxidative damage. Vegetable oil is composed mostly of medium-chain or long-chain fatty acids which exist as triglycerides. Although there are literatures which deal with the penetration of specific natural oils into hair there is a lack of research which provide the empirical data that can be used to explain the penetration of larger population of vegetable oils. This research was aimed to examine whether the chain length of fatty acid affect the penetration of fatty acid and protection in hair and also to apply the results on explaining the protective effect of Medium-Chain Triglyceride oil (MCT oil) and Coconut oil. Nine different hair treatments were formulated with three medium-chain fatty acids (C8:0, C10:0, C12:0), three long-chain fatty acids (C14:0, C16:0, C18:0), MCT oil, Coconut oil, and a blank. Composition of fatty acids of hair was examined by the Gas chromatography mass spectrometry. Penetration of fatty acid in hair was examined by the UV–VIS spectrophotometry. Protection of damaged hair was examined by the differences in color, tensile strength, thickness, and the concentration of protein leak of 21-day vs. 0-day measurements. Results of t-test indicated that the penetration and the protection of the medium-chain fatty acid was significantly better than those of the long-chain fatty acid, and that MCT oil and coconut oil were not significantly different.